1. Field of the Invention
This invention relates to generally to the actuation train of an automotive brake assembly and more particularly to an improved push rod button utilized in such a train, and a manufacturing method of making such a push rod button.
2. The Prior Art
The prior art is exemplified by my prior U.S. Pat. No. 4,901,426 issued Feb. 20, 1990 in which there is disclosed a push rod button made and constructed in accordance with the past practice. With such a construction, the work piece is generally selected as a solid piece of metal. The work piece is then subjected to machining operations during which the push rod button is formed into its characteristic configuration. A generally cylindrical cup shaped recess is formed for the purpose of receiving and seating a reaction disc made of rubber, or other suitably elastic and resilient material. Coaxially disposed and extending longitudinally from the bottom wall of the recess in an opposite axial direction, there is provided a reduced diameter cylinder in which is received a shaft part of the push rod constituting one of the elements of the drive train.
Such machining operations are customarily performed on an automatic screw machine. The machine function performed is a precision metal cutting operation, therefor necessitating the time and attention of a skilled machine operator and set-up man, a relatively costly form of manufacturing endeavor. Further, the metal cutting action necessitates the use of an elaborate liquid cooling system in which is circulated a sufficient amount of cutting oil and cutting lubricant so that the handling of the oil or lubricant presents a formidable environmental problem. Lastly, the manufacturing technique generates metal shavings and cuttings as scrap material that must be separated from the lubricant or cutting oil and the disposal of which exacerbates the environmental problems attendant upon producing the product.